Hydraulic fracturing has been an important technique to enhance production of hydrocarbon from oil and gas bearing formation. In a typical hydraulic fracturing treatment, hydraulic fracturing fluid containing a solid proppant is injected into the formation at a pressure high enough to cause or enlarge a fracture in the reservoir. When the hydraulic fracturing fluid is removed, packed proppant can keep the fracture open, allowing fluids to flow from the formation through the proppant to the production wellbore. The proppant is of extreme importance as it provides a long-term conductivity of the fracture.
The main function of proppants is to provide and maintain conductive fractures where proppants should meet closure stress requirement and show resistance to diagenesis under downhole conditions. Different proppants have been developed to meet the requirement of enhancing production of hydrocarbon with various materials, sizes and shapes. Many materials have been used as proppants including silica sand, glass and ceramic. The hydraulic fracturing fluid carrying the proppant in the fracture generally contains water, polymer, crosslinker, fluid loss additives, surfactants, flow back additives, surfactants, clay stabilizers, proppant, and gel breaker. The polymer is used to provide viscosity and keep the proppants suspended until they have reached their desired location in the fracture. The breakers are used to reduce the polymer viscosity, allowing the particles to settle and the liquid portion of the fracturing fluid to be returned to the surface when the external pressure is removed. The proppants remain in the fracture and form permeability channels to increase the oil or gas production.
The success of the fracturing treatment may depend on the permeability of the proppant. U.S. Pat. No. 7,581,590 to Timothy Lesko et al. discloses a method of heterogeneous proppant placement in a fracture. The method is based on the concept that proppant can be placed discontinuously within the fracture. This technique uses a pumping scheme where proppant is added in short pulses, alternating with pulses without proppant. Specialized fibers render the integrity of the proppant pulses by binding the proppant particles together, thus keeping the proppant in the form of individual clusters in the fracture. In this way, hydrocarbons can flow through the channels separating the proppant clusters rather than flowing through the proppant pack itself as in conventional fractures. From this principle, the conductivity of the channel fracturing technique would well exceed that of a continuous proppant pack, resulting in improved hydrocarbon productions.
The conventional proppants have certain disadvantages such as formation and fracture permeability damage due to the viscous gel residue, risk of early screen-out and reduced effective propped area due to proppant excessive leakoff or settling, and abrasion to the pumping equipment and tubular. To eliminate the effect of some disadvantages, and have more application potential, U.S. Pat. No. 9,834,721 to Fakuen Frank Chang et al. discloses a chemical composition and method for converting injected fracturing fluid into a permeable proppant pack in-situ.
It would be advantageous to develop a fracturing fluid to improve conductivity of the proppant.